Historical weather data, all-time temperature records, and monthly climate averages for Johnston, RI. Explore typical weather conditions by week for trip planning, and see how today compares to the historical record.
April 4th in Johnston runs mild but unpredictable — expect a high around 54° and a low near 36°, with a coin-flip chance of rain. The date has swung wildly over 78 years of records, from a balmy 76° in 2010 down to a brutal 14° back in 1954. Snow is unlikely but not impossible, with about a 4% chance.
Johnston's weather has real teeth at the extremes — the thermometer has hit 104° in August and plunged to -13° in January, a swing of 117 degrees. A single August storm in 1979 dumped 6.31 inches of rain, and a February 2026 snowstorm buried the area under a staggering 35.5 inches in one day.
Summer is the sweet spot, with average highs peaking around 83° during the third week of July, while mid-January is the depths of winter at a frigid 36°. The wettest stretch of the year actually falls in late March through early April, averaging over an inch of precipitation per week. If you're planning a visit, June through September offers the most reliably pleasant conditions.